It's because those people don't have ther own tuning software and have likely never used a wideband.
I've seen guys with $60,000 caddys ask why they should need a wideband sensor after they have already dropped another 5 grand in mods on the car. Like it never even dawned on them that they needed to watch this kinda stuff when you are making 700whp.
ZZP is one of the people that has told me this.
00 Grand Prix GT, top swapped, .020 FMP, GT1 Cam, SFI Crank pulley, SSM90, 3.3 MPS, ZZP ported Gen 3/LIM, ported heads, #90's, N* TB, SLP Intake/Headers/Catback, F-body brakes, KYB AGX, Aeroforce, AEM, 93 octane.